Friday, April 27, 2012

PLANTS






Hey, I made it back to the future!!!  You see, I just got back from a trip to prehistoric time in my time machine.  I went to find out where the first plants came from.  I went back 300 million years to find out the answer, but when I got there I saw plants everywhere.  Well since I need a quick answer for science class, I will head to the internet and my science textbook.  I found out that nobody knows the answer for sure, but scientist have strong evidence to come up with an answer.  According to scientist, 3000 million years ago green algae was the first living organisms to appear which resembled a plant.  Oh, now I see where I went wrong, I did not go back far enough in my time machine.

The green algae is not a plant but a type of protists.  When it appeared the green algae was a one-cell organism that lived in the ancient seas.  This one-celled organism then started developing thick cell walls and the green color known as chlorophyll which helped them to make food from the air, water and soil.  Did you know when the green algae first appeared on Plant Earth the atmosphere was unlivable for all creatures which breathe oxygen?  Back then the air was only carbon dioxide, a gas with is deadly to us but needed by the green algae.  Then this green algae through photosynthesis was able to clean the atmosphere and fill it with oxygen for future organisms to appear.  Slowly over time, I mean millions of years,  the green algae was was able to leave the water and adapt to land growing and producing multi-cell organisms known as plants.  Thanks green algae for helping evolution to happen. 

Since the green algae is still in our seas today, scientist used the following evidence to come up with the conclusion of where plants came from.  
1.  The green algae and plants have a similar cell wall.
2.  The green algae and plants both contain chlorophyll.
3.  The green algae and plants both store their energy in the form of starch.
4.  The green algae and plants have the same life cycle.
5.  The green algae and plants are similar in color.

This is a picture of green algae which covered a beach in China.  Although it looks scary, it is harmless and the kids are having fun swimming in the green algae.

Check out all this green algae!


What are the Characteristics of Plants?

What makes a plant a plant????? These are the following characteristics of a plant:

1.  Multi Cellular - This means all plants have many cells.  Plant cells have a cell wall made of cellulose which gives plants its ridge shape.  This is a plant cell.




2.  Eukaryotic Cells - This means that the plant cells have successfully adapted to life on land.  Plants cells allow them to be able to live in the most extreme environments.  You can find plants from Antarctica to the hot and dry deserts of Africa.

Plants in the desert.

3.  Chlorophyll - Plants have a green pigment called chlorophyll.  With Chlorophyll plants are able to make their own food using sunlight and carbon dioxide.

This is chlorophyll under a microscope.


4.  Cuticles - Have you every looked at a leaf closely?  You will notice this waxy layer on the leaf.  Well, plants have a waxy layer that coats the stems and leaves, and other parts of the plant that protects it from exposure to the air and sun.

Notice the shine from the waxy coating on the leaf.



What is the difference Between Vascular and Non Vascular Plants?

You see, all plants are broken down into two main groups.  They are known as Vascular or Nonvascular.  Don't worry, I too had never heard of these terms until I started learning about plants.  But once I explain what they mean, it should be very easy.


Did you know that vascular plants make up about 80% of all plants?  Well what makes a plant Vascular is the special tissue in its stem.  This tissue allows water and nutrients to move up and down the plant.  It is sort of how our blood vessels allow blood to move up and down our body to provide the nutrients and the oxygen we need to survive.  This up and down movement of water and nutrients help the plant to grow and get bigger and bigger.  Examples on Vascular plants is an Orchid and the Red Oak Tree.
 
This is an Orchid flowering plant.


This is a Red Oak Tree.



Now on to Nonvascular plants.  Since you know what vascular plants are, well Nonvascular is simple.  Basically, non vascular plants do not have the special tissue like Vascular plants to move water and nutrients up and down the plant.  I know that you must be wondering.   Well how do they grow?   Since they do not have this special tissue they have to be able to feed and drink when the environment provides it.  Have you ever noticed moss only grows where it is always moist.  Examples of Nonvascular plants are Moss and Liverwort.  


I am sure you have seen this.  This is Moss.
 
This is Liverwort.


The Three Differences Between Vascular and Nonvascular Plants are:


1.  Vascular Plants have roots but Nonvascular plants do not.
2.  Vascular Plants have stems to take water and nutrients up and down the plant but Nonvascular plants do not.
3.  Vascular plants have leaves to take up water and Nonvascular plants do not.


Remember, I told you that this would be easy.


I hope that you have enjoyed my post on plants.  I learned a lot preparing for this post, I hope you learned something new.  Until my next post, bye and I hope to see you soon.  Hasta La Vista.